﻿Shader "Custom/UIImageOutline" {
	Properties {
		_MainTex ("Sprite Texture", 2D) = "white" {}
                                 _Color ("Tint", Color) = (1,1,1,1)

			_StencilComp ("Stencil Comparison", Float) = 8
			_Stencil ("Stencil ID", Float) = 0
			_StencilOp ("Stencil Operation", Float) = 0
			_StencilWriteMask ("Stencil Write Mask", Float) = 255
			_StencilReadMask ("Stencil Read Mask", Float) = 255
			_ColorMask ("Color Mask", Float) = 15
			[Toggle(UNITY_UI_ALPHACLIP)] _UseUIAlphaClip ("Use Alpha Clip", Float) = 0
			_OutlineColor("Outline Color", Color) = (1,1,1,1)
			_OutlineWidth("Outline Width", Float) = 2

			_Threshold("Threashold",Range(0,1)) = 0.5
	}
		SubShader{
				Tags
				{
					"Queue"="Transparent"
"IgnoreProjector"="True"
"RenderType"="Transparent"
"PreviewType"="Plane"
"CanUseSpriteAtlas"="True"

				}
				Stencil
				{
					Ref [_Stencil]
Comp [_StencilComp]
Pass [_StencilOp]
ReadMask [_StencilReadMask]
WriteMask [_StencilWriteMask]

				}

				Cull Off
Lighting Off
ZWrite Off
ZTest [unity_GUIZTestMode]
Blend SrcAlpha OneMinusSrcAlpha
ColorMask [_ColorMask]

			  Pass
			  {
			   CGPROGRAM



					#pragma vertex vert
					#pragma fragment frag

					#include "UnityCG.cginc"
					#include "UnityUI.cginc"
					#pragma multi_compile __ UNITY_UI_ALPHACLIP

			   struct appdata_t 
		       {
					   float4 vertex : POSITION;
					   float4 color :COLOR;
					   float2 texcoord : TEXCOORD0;
		        };

		       struct v2f 
		       {
				  float4 vertex : SV_POSITION;
fixed4 color : COLOR;
half2 texcoord : TEXCOORD0;
float4 worldPosition : TEXCOORD1;
			   };

			  fixed4 _Color;
fixed4 _TextureSampleAdd;
float4 _ClipRect;

			   v2f vert(appdata_t IN)
			   {
				  v2f OUT;
OUT.worldPosition = IN.vertex;
OUT.vertex = UnityObjectToClipPos(OUT.worldPosition);
OUT.texcoord = IN.texcoord;
#ifdef UNITY_HALF_TEXEL_OFFSET
OUT.vertex.xy += (_ScreenParams.zw-1.0)*float2(-1,1);
#endif
OUT.color = IN.color * _Color;
return OUT;
			   }


			  sampler2D _MainTex;
float4 _MainTex_TexelSize;
float4 _OutlineColor;
float _OutlineWidth;
float _Threshold;
			   fixed4 frag(v2f IN) : SV_Target
			   {
				   half4 color = (tex2D(_MainTex, IN.texcoord) + _TextureSampleAdd) *
IN.color;
color.a *= UnityGet2DClipping(IN.worldPosition.xy, _ClipRect);
#ifdef UNITY_UI_ALPHACLIP
clip (color.a - 0.001);
#endif
float width = _MainTex_TexelSize.z, height = _MainTex_TexelSize.w;
if (color.a <= _Threshold)
{
half2 dir[8] = {{ 0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1},
{-1,0},{-1,1}};
for (int i = 0; i < 8;i++)
{
float offset = float2(dir[i].x / width,dir[i].y / height);
offset *= _OutlineWidth;
half4 nearby = (tex2D(_MainTex,IN.texcoord + offset) +
_TextureSampleAdd) * IN.color;
if (nearby.a > _Threshold)
{
color = _OutlineColor;
break;
}
					   }
				   }
				   return color;
			   }
				   ENDCG
		      }
		
		}
	}

